The present invention relates to a releasable buckle, particularly for bags, satchels and similar, the said buckle comprising an essentially-plate-like female part, the latter having a receiving opening at one end and an adjacent locking edge on the opposite side to the said receiving opening, and a male part comprising a locking portion, the latter engaging behind the locking edge when the male part is inserted inside the said receiving opening, and an activating portion located in front of the locking portion in the male part insertion direction. On known buckles of the aforementioned type, the activating and locking portions are formed respectively on the root portion and free end of a flexible tongue carried on the front end and facing the rear end of the male part, in the insertion direction of the latter inside the female part. The said male part is essentially a rigid plate having the said flexible tongue at one end and, at the opposite end, a member enabling connection to sheet material such as a belt or the flap on a bag or satchel. One of the main drawbacks on known buckles of the aforementioned type is that, for locking and releasing the male part inside the female part, the said flexible tongue is required to deflect considerably for enabling the locking portion on the said free end of the said flexible tongue to fit underneath the said locking edge and so enable passage of the same through the said receiving opening. Such entails relatively strong effort on the part of the user, relatively slow operation with the possibility of the buckle getting jammed, particularly when opened, and the danger of the flexible tongue being broken and the buckle thus being rendered unusable, owing to severe fatigue caused by the relatively severe bending strain the buckle is subjected to.